UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0

Steps to reproduce the problem:
1. Visit https://jsfiddle.net/zv2nLo6u/15/ and wait one second.

What is the expected behavior?
The text "Hello world." stays visible.

What went wrong?
The text "Hello world." becomes invisible.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 70.0.3535.4  Channel: canary
OS Version: 10.0
Flash Version: Shockwave Flash 30.0 r0

If you add a style `transform: translateZ(0)` to the element `#fixed-text`, the element becomes visible again.